Recently, lamination of an elastomer layer on a hard resin molded article has been practiced to improve the air-tightness and moisture resistance to prevent leakage of gas, liquid and the like, the shock absorption of a molded article, the non-slip effect, or the touch.
In order to achieve these objectives, conventionally styrene-based elastomer or olefin-based elastomer which is excellent in flexibility has been laminated on a hard resin molded article. However, since hard resins other than the olefin-based resins such as polypropylene and the like, for example, an ABS resin or a polycarbonate resin have poor heat thermal adhesiveness with a styrene-based elastomer or an olefin-based elastomer, a composite molded article of such resin and elastomer is produced by providing a convexo-concave surface on the part to be bound, coating the core article partially with a surface layer material, joining them mechanically by extending the surface layer material to the backside of the core article through a hole made therein, or applying the one such as a primer, which works on the part to be bound as an adhesive agent. As a result, the obtained composite molded article had problems such as inferior adhesiveness, increased complexity of the structure and increased number of processes, and the like. Furthermore, even if a polar thermoplastic elastomer such as a polyamide-based elastomer, a polyurethane-based elastomer, or a polyester-based elastomer is laminated alone on a hard resin molded article such as an ABS resin or a polycarbonate resin, the balance of flexibility, heat adhesiveness and moldability remains insufficient.
In an attempt to solve such problems, in Patent Documents 1 to 6 are disclosed methods in which a polyamide-based elastomer, a polyurethane-based elastomer, a polyester-based elastomer or the like is added to the styrene-based elastomer to be laminated. However, even such methods do not provide a product which is well-balanced in flexibility, heat adhesiveness and moldability, moreover, there are shortcomings of hydrolysis, and the like, and thus the demands of the market were not quite met.
On the other hand, the Patent Document 7 proposes a composition characterized by containing two components, that is, an acryl-based block copolymer and an olefin-based polymer containing a styrene-based elastomer or an olefin-based elastomer. However, in the composition containing those two components only, there was room for improvement in tensile strength and the like, because of the insufficient dispersion of the two components.    Patent Document 1: Japanese Patent Laid-Open Publication No. H01-139240    Patent Document 2: Japanese Patent Laid-Open Publication No. H03-100045    Patent Document 3: Japanese Patent Laid-Open Publication No. H03-234745    Patent Document 4: Japanese Patent Laid-Open Publication No. H06-65467    Patent Document 5: Japanese Patent Laid-Open Publication No. H08-72204    Patent Document 6: Japanese Patent Laid-Open Publication No. H10-130451    Patent Document 7: Japanese Patent Laid-Open Publication No. 2005-54065